Hearing aid ear wax guard and a method for its use

ABSTRACT

For the protection of an in-the-ear hearing aid against contamination by ear wax through the acoustic outlet port ( 34 a) or a vent, a replaceable ear wax guard ( 36 ) is inserted in the aid and includes an essentially tubular element with a through-going cavity and an abutment collar in one end for sealing abutment against the hearing aid housing ( 31 ). For an easy and safe insertion and removal of the ear wax guard ( 36 ), an applicator is used, which in one end has a smooth pin for introduction in the through-going cavity of the ear wax guard ( 36 ) and in the other end a harpoon-shaped catch member. For mounting of the ear wax guard ( 36 ) a hose or tube member serving as acoustic outlet canal ( 34 ) is connected to an abutment collar ( 33 ) in abutment with the outside of hearing aid. The abutment collar is designed with oversize standard dimensions and adapted to an individually user-adapted hearing aid housing by preparation of its periphery edge.

This is a divisional of U.S. application Ser. No. 10/926,005, filed Aug.26, 2004, which is a divisional of application Ser. No. 09/743,316 filedJan. 9, 2001, now U.S. Pat. No. 6,795,562, which is a national stageentry of PCT/DK99/00022 filed Jan. 15, 1999, which claims priority fromDanish Application PA199800921 filed Jul. 10, 1998, the disclosures ofwhich are incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to a replaceable ear wax guard forplacement in an opening in a wall part of a housing of an in-the-earhearing aid designed for positioning in the ear canal, comprising anessentially tubular element partially closed in one end by an ear waxretaining barrier.

In in-the-ear hearing aids where the hearing aid housing is placedwithin the user's ear canal with the acoustic outlet port facing theinner ear and connected to the telephone unit of the hearing aid, it isa well-known problem that the acoustic outlet passage is exposed tocontamination with cerumen or ear wax which may lead to clogging of theacoustic outlet passage with consequently reduced sound reproduction. Atworst, there may be a risk for the ear wax to enter the hearingapparatus housing and result in damage to the electrical components ofthe hearing aid.

In order to avoid this problem, it is known from U.S. Pat. No. 4,972,488to arrange a replaceable ear wax barrier, which can at the same timeprovide a dampening of the acoustic response, in the acoustic outletpassage in the apparatus housing. In this known design, the ear waxbarrier is formed as a screw plug the arrangement of which presupposes athread being provided in the acoustic outlet passage, and the ear waxbarrier is in the end facing outward at the insertion by screwing,designed with incisions for providing a slot for a screw driver. Thebarrier effect for retaining of ear wax is obtained by providing inwardprojections in a through-going cavity in the screw plug.

As a consequence of the very small dimensions where the acoustic outletpassage has typically a diameter of about 1 mm, the screw plug formentails that insertion and removal of the ear wax guard is a ratherdifficult operation, especially for weak-sighted hearing aid users, andthe inward projections forming a kind of maze in the through-goingcavity do not provide full security against migration of ear wax.Furthermore, the screw plug design cannot be used in in-the-ear hearingaids of the conventional type where the acoustic outlet passage isformed by a short hose or tube member connecting the telephone unit withan acoustic output port in the wall of the hearing aid housing.

Furthermore, the international patent application WO 84/04016 disclosesan ear wax guard in the form of an outwardly closed plug with adisc-shaped head which at the placement of the plug covers the acousticoutlet port of the aid housing. In the plug under the disc-shaped head,there are provided radial acoustic passageways in connection with alongitudinal acoustic passageway opening in the plug end introduced inthe aid housing. To secure a sufficient acoustic passage, the plug isdesigned such that the disc-shaped head is kept at a distance from theoutside of the aid housing which entails a risk, albeit reduced, ofmigration of ear wax under the plug and in the narrow radial acousticpassageways. As a consequence of the smooth disc-shaped head, theinsertion and removal of the plug is also in this case a difficultoperation.

In a hearing aid known from U.S. Pat. No. 4,553,627, an essentiallymushroom-shaped ear wax guard with a crossing acoustic passage ismounted with snap engagement in a metal ring inserted in the acousticoutlet port of the hearing aid housing.

In published European application EP 0724 377 A1, an ear wax barrier ofthe kind defined above is disclosed, which is inserted by press-fittingin the receiver tube of a hearing aid with frictional engagement betweena lip provided by the wax barrier and the receiver tube. Thereby,removal or dislodging of the wax barrier will be resisted. Whereas theoperation of removal is not described in the document the onlypossibility would appear to seize a projecting collar formed at thedistal end of the wax barrier by a suitable instrument, such as a knife,a tongue or a pair of tweezers.

With this prior art as background, it is the object of the invention toprovide a replaceable ear wax guard of the stated type with a simple andlow-cost design suited for all kinds of in-the-ear hearing aids andwhich by use of an applicator can be mounted in and removed from the aidhousing in a simple way.

SUMMARY OF THE INVENTION

For this purpose, the ear wax guard according to the invention ischaracterized in that the tubular element provides an essentiallycircular cylindrical through-going cavity with a smooth inner side andis connected in the opposite end to a surrounding abutment collarforming, in the position of use of the ear wax guard, a sealing lipagainst said wall part around said opening, the tubular element beingmade by an elastically yielding material which, by introduction of anapplicator into the tubular element, is engageable by a catch member ofsaid applicator for removal of the ear wax guard from an acoustic outletport or vent formed by said opening.

As a consequence of the simple design as a short tubular element with asurrounding abutment collar in the end facing inward at the insertion,the ear wax guard according to the invention is inexpensive tomanufacture in a large number by molding of the elastically yieldingmaterial, which can typically be silicone rubber or a thermoplasticelastomer. A further contribution to this is the positioning of the earwax retaining barrier in one end of the tubular element which whenintroduced is led into the acoustic outlet canal. The merely partialopening of this end of the tubular element can be obtained by designingthe guard as a kind of screen and thus can assure a good soundtransmission.

Advantageous features and embodiments of the ear wax guard are describedbelow. In a particularly advantageous embodiment, in particular for usein connection with CIC hearing aids, the abutment collar is providedwith a convex outside and a concave or faintly conical underside toprovide said sealing lip at its peripheral edge. Thus, the user comfortis improved as the ear wax guard essentially follows the outer contourof the aid housing.

As a consequence of the sealing engagement of the abutment collar of theear wax barrier against the hearing aid housing, the abutment collar,which can preferably be provided with a relatively thin and soft edge,fitting snugly to the surrounding outside of the housing with a veryeven transition, it is avoided that when inserting or removing thehearing aid, the abutment collar causes any inconvenience or damage tothe ear canal.

As the removal of the wax barrier of the invention by seizing the edgeof the abutment collar in a conventional way as known, e.g., from U.S.Pat. No. 4,553,627, is not possible, the invention further relates to anapplicator for placement and replacement of the ear wax guard in anopening in a wall part of a housing of an in-the-ear hearing aiddesigned for positioning in the ear canal, comprising an essentiallyrod-shaped member provided in one end with first engaging means fittinginto the tubular element of the ear wax guard for insertion of the earwax guard and, in the opposite end, with second engaging means forremoval of the ear wax guard.

In a prior art design of a similar applicator disclosed in U.S. Pat. No.4,972,488, the first engaging means is formed with projecting finsengageable with recessed slots in the inner side of the tubular elementof the wax guard, whereas the second engaging means projecting memberswith fins engageable with the projecting collar of the wax guard.

According to the invention, such an applicator is characterized in thatsaid first engaging means comprises a smooth pin fitting into the smoothwall inner side of the tubular element of the ear wax guard, whereassaid second engaging means comprises a catch member engageable with theelastically yielding material of the tubular element at said smooth wallinner side by introduction of said opposite end of the applicator intothe tubular element.

By this applicator design, the insertion of the ear wax guard in theacoustic outlet port and the removal herefrom in connection with thereplacement of the ear wax guard can be made in a simple way and with ahigh degree of security even by weak-sighted users, the different designof the two ends of the applicator for insertion and removal,respectively, contributing to the easy operation.

Advantageous embodiments of the applicator are also described below andin the appended claims. Thus, according to a preferred embodiment, theessentially cylindrical and wedge-shaped portion of the applicator isseparated by an intermediate piece with a cross section larger than saidportion, and a magnifying lens having a bore is provided for attachmenton said cylindrical or said wedge-shaped applicator portion in abutmentagainst said intermediate piece.

By itself, the use of a magnifying lens in combination with aconventional screwdriver is known from French patent publication FR 2347 158.

Thus, a further improvement of the operating security is obtained,especially for weak-sighted hearing aid users.

As from consideration of the visibility of the through-going cavity ofthe ear wax guard and the risk of pressing ear wax accumulated in theear wax guard out through the ear wax retaining barrier at introductionof the applicator in the ear wax guard in connection with the removalhereof, the catch member may not cover a too large area, the use of theapplicator, especially in ITE hearing aids where the acoustic outletcanal is designed as a hose or tube member guided from the outputtransducer of the aid all the way through to the acoustic outlet port inthe wall of the housing, will entail a certain risk that such a hose ortube member and perhaps the ear wax guard itself at the pressing-in ofthe catch member is pressed into the hearing aid housing.

To encounter this risk, the invention relates in addition to aparticularly designed in-the-ear hearing aid with a housing provided forpositioning in the ear canal and having an essentially shell-shapedwall, in which in an end part meant for placement inside the ear canalan opening is provided to form an acoustic outlet port in connectionwith one end of hose or tube member serving as acoustic outlet canal,the other end of which is retained in an outlet port from an outlettransducer arranged in the housing or optionally a vent.

To obtain an improved security against the hose or tube member servingas acoustic outlet canal at the mounting or replacement of the ear waxguard being detached from its connection with the acoustic outlet portin the end part of the housing wall and pressed into the housing, thehearing aid according to the invention is characterized in that topermit placement and replacement of an ear wax guard as defined above byuse of an applicator as likewise defined above without affecting thehose or tube member, said opening is provided in an annular abutmentcollar arranged in abutment with the outside of said wall end part.Appropriate embodiments of such a hearing aid are further describedbelow.

Since the housing for in-the-ear hearing aids of the stated kind isusually designed with an individually adapted form according to theactual user's ear canal, the invention further relates to a method formanufacture of a hearing aid of the stated type which permits aproduction of the abutment collar for mounting of the ear wax guard in astandard design independent of the individual user adaptation of theform of the housing.

According to the invention, this method is characterized by the use ofan abutment collar having overdimensions with respect to said end partof the housing wall, and that a flush transition of the abutment collarwith the outside of said end part is provided by preparation of theperipheral edge of the abutment collar.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further explained in the following with reference tothe schematical drawings, wherein

FIG. 1 is a sectional view of a part of the housing of an in-the-earhearing aid,

FIG. 2 a section of FIG. 1 on a larger scale,

FIGS. 3 and 4 are perspective views of an embodiment of the ear waxguard,

FIG. 5 is a perspective view of an embodiment of an insertion andremoval applicator,

FIGS. 6 and 7 show on a larger scale sections of the applicator in FIG.5.

FIG. 8 shows an embodiment of an enlargement lens mounted on theapplicator in FIG. 5,

FIG. 9 shows an alternative design of the enlargement lens,

FIG. 10 at a)-d) illustrates insertion and removal of the ear wax guard,

FIG. 11 is a sectional view corresponding to FIG. 2, showing the endpart of the housing in an embodiment of a hearing aid especiallydesigned for positioning of the ear wax guard according to theinvention,

FIG. 12 is a modification of the embodiment in FIG. 11, and

FIGS. 13-17 illustrate a method for use in production of the hearing aidaccording to the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows the portion 1 facing the inner ear, of the housing of anin-the-ear hearing aid designed for position in a user's ear canal. Ofthe internal components in the hearing aid only an outlet transducer isshown in the form of a telephone unit 2 with an output port 3 whichthrough an acoustic outlet canal 4 formed by a hose member of plasticsis connected to an acoustic outlet port 4a designed in an end wall part5 of the housing portion 1. In order to avoid contamination of theinterior of the housing portion 1 with cerumen or ear wax enteringthrough the acoustic outlet canal 4, an ear wax guard 6 is placedherein.

The embodiment shown in FIGS. 2-4 of the ear wax guard 6 is according tothe invention designed as a short, essentially circular cylindricaltubular element 7 with a length and an outer diameter adapted tointroduction into the acoustic outlet canal 4 with frictional fit.

A through-going also essentially circular cylindrical cavity 8 in thetubular element 7 is in one end, which by insertion in the acousticoutlet canal 4 is led into this, partially closed by an ear waxretaining barrier 9 which as shown in FIG. 4 may have the form of ascreen with loops limited by radial threads 10.

In the opposite end the tubular element 7 is surrounded by an abutmentcollar 11 which in the inserted position is brought into sealingabutment against the end wall part 5 around the acoustic outlet port 4a.In the shown embodiment the abutment collar 11 has a convex outside anda concave or faintly conical underside, the peripheral edge of thecollar forming a relatively thin and soft sealing lip 12 against the endwall part 5. Thus, a high degree of security is obtained againstmigration of ear wax under the periphery edge of the collar and the earwax guard will in inserted position follow the contour of the aidhousing which is of considerable importance as to comfort, especially atso called CIC aid which are placed in the innermost sensitive part ofthe ear canal.

The ear wax guard 6 is manufactured of elastic yielding material as e.g.silicone rubber or a thermoplastic elastomer and typical with an outerdiameter of 1.25-1.5 mm and an inner diameter of the cavity 8 of about 1mm.

For an improved securing of the ear wax guard 6 in the acoustic outletcanal 4, the tubular element 6 can on the outside be provided with meansfor frictional engagement, e.g. in the form of at least onecircumferential bead 13.

An ear wax guard as shown and described can be placed not only in theacoustic outlet port of the hearing aid housing, but also in an openingfacing the inner of the ear canal, in the hearing aid housing for a ventpassage, which may have the purpose of preventing or reducing so calledocclusion effects.

A means for use at insertion and removal of the ear wax guard 6 in FIGS.2-4 comprises an essentially rod-shaped applicator 14 which in theembodiment shown in FIGS. 5-7 in one end has an essentially circularcylindrical portion 15 and in the other end an essentially wedge-shapedportion 16 formed by bevels 17 and 18 and with a flat rectangular endedge face 19. The end portions 15 and 16 are separated by anintermediate piece 20 which is connected with the end portions 15 and 16through circular cylindrical transition portions 21 and 22, and theintermediate piece 20 has a cross-sectional dimension which is largerthan the adjacent transition portions 21 and 22 as is further explainedin the following.

At the free end of the circular cylindrical portion 15, the applicator14 is provided with a smooth circular cylindrical pin 23 for insertionin the inner cavity 8 of the ear wax guard 6 in connection with theinsertion of the ear wax guard in the acoustic outlet port 4. In theopposite end, the applicator 14 is provided with a harpoon-shapedpressing-in peak 24 projecting from the end edge surface 19 which withcatch edges 25 forms a catch member for engagement with the wall innerside of the tubular element 7 of the ear wax guard 6 around the cavity 8in connection with removal of the ear wax guard.

Corresponding to the flat rectangular form of the end edge surface 19,the pressing-in peak 24 is formed as a four-sided pyramid with a flatrectangular base. The pressing-in peak 24 is dimensioned such that thelong side in the base is larger than the diameter of the through-goingcavity 8 of the ear wax guard, the pressing depth being limited so thatthe pressing-in peak 24 is prevented from being pressed too far into thecavity 8 such that the ear wax accumulated in the ear wax guard 6 is notpressed through the guard 9 and into the aid housing 1.

As a consequence of the small dimensions, it is appropriate especiallyfor weak-sighted hearing aid users, if the insertion and removal meanscomprises an enlargement lens designed to be positioned on the actuallyused end portion 15 or 16 of the applicator 14.

In a simple embodiment, such an enlargement lens can as shown in FIG. 8comprise a plano-convex lens 26 in the optical axis of which there isprovided a bore 27 suitable for arrangement of the lens on a transitionportion 21 or 22 of the applicator 14 in engagement with theintermediate piece 20.

In order to avoid that the end portion 15 or 16 of the applicator 14extended under the lens during insertion or removal covers the wantedvisual field, a bore 28 provided for the attachment of the lens on theapplicator 14, as shown in FIG. 9, can in an alternative design beformed in a flange element 29 projecting from the periphery of the lensand forming such an angle with the symmetry plane of the lens 30perpendicular to the optical axis that the focus of the lens is locatedimmediately outside the free end of the relevant end portion 15 or 16.

When inserting the ear wax guard, this is placed as shown in FIG. 10a onthe smooth pin 23 at the end of the end portion 15 of the applicator 14and can thus, perhaps by using an enlargement lens as shown in FIG. 8 or9 easily and securely be guided into the acoustic outlet port 4a and beretained with frictional fit in the acoustic outlet canal 4 formed bythe hose member whereupon the applicator is removed as shown in FIG.10b.

When a quantity of ear wax has been accumulated in the ear wax guardentailing a significant reduction of the sound reproduction of thehearing aid, the ear wax guard can as shown in FIG. 10c be removed byguiding the pressing-in peak 24 of the applicator 14 into the cavity 8of the ear wax guard until the catch edges 25 enter into engagement withthe surrounding wall inner side, the ear wax guard 6 being brought alongat the subsequent removal of the applicator as shown in FIG. 10d.

In the embodiment shown in FIG. 11 of a particularly designed hearingaid according to the invention, the ear wax guard 36 which can bedesigned as shown in FIG. 3 or 4 is mounted in a bushing 32 with anannular abutment collar 33 in abutment against the outside of the endwall part 35 of the housing portion 31. The bushing 32, which ispreferably made of a material with a larger rigidity, e.g., plastics ormetal, than both the elastic hose member serving as acoustic outlet port34 and the ear wax guard, is in this embodiment mounted internally inthe hose member 34 such that this is squeezed against the edge side ofthe acoustic outlet port 34a. The bushing 32 can, e.g., be maintained inthe end of the hose member 34 by gluing or welding of the abutmentcollar 33 to the end wall part 35 and/or it can be inserted with apressure fit in the hose member 34.

The annular abutment collar 33 and the bushing 32 provide a cylindricalbore for mounting the ear wax guard 36 which can be effected with ameans in the form of a rod-shaped applicator as described above withreference to FIGS. 5-10. The abutment collar has in this connection suchan inner diameter that it cannot be passed by the abutment faces of theapplicator around the pin 23 and the harpoon peak 24.

The periphery edge 37 of the abutment collar 33 is as shown preferablyprepared such that a flush transition is obtained between the abutmentcollar and surrounding outside of the end wall part 35.

By means of the abutment collar 33 which in the shown embodiment is infixed connection with the hose member 34 through the bushing 32, thereis obtained a considerably improved security against unintentionaldetachment of the hose member 34 from the acoustic outlet port 34a atthe mounting or replacement of the ear wax guard 36 by means of anapplicator as shown in FIGS. 5-10 with the risk that the hose member 34is pressed completely into the hearing aid housing 31.

In the modification of this hearing aid design shown in FIG. 12, themounting bushing 42 is with the abutment collar 43 adapted to be mounteddirectly in the acoustic outlet port 44a. The hose member serving asacoustic outlet canal can be mounted on the outside of the bushing 42 inthe same way as shown in FIG. 11, but alternatively the hose member 44can as shown be maintained inside the mounting bushing 42. In order toavoid, in this embodiment, the risk of an applicator as shown in FIGS.5-10 entering into contact with the hose member 44 itself, the abutmentcollar is preferably provided with a narrowed bore 46 for mounting ofthe wax guard, preferably with the same diameter as the internaldiameter of the hose member 44.

Since the hearing aid housing for in-the-ear hearing aids is usuallydesigned with individual adaptation to the form of the actual user's earcanal, it is in FIG. 13 illustrated how an abutment collar 53 as shownhere without a mounting bushing can be obtained by using an abutmentcollar 53 with overdimensions in relation to the end part 55 of thehearing aid housing 51 and preparation of the periphery edge 56 of theabutment collar 53, firstly by cutting to a suitable diameter as shownby 57 and then by grinding to obtain a flush transition against theoutside of the end part 55. Also in the embodiments shown in FIGS. 11and 12, the bushings 32 and 42 with the abutment collars 33 and 43 canin a corresponding way be manufactured in a standard design with anoverdimensioned abutment collar which can be adapted to the end part ofthe hearing aid housing by preparation in the same way.

As shown in FIGS. 11-13 it is usually most appropriate, e.g., for costreasons, that the abutment collar, whether provided with a mountingbushing or for direct connection with the hose member serving asacoustic outlet canal, is designed as a ring disc with a flat undersidefor abutment against the end part of the hearing aid housing. In thisconnection, the end part 55 of the hearing aid housing can as shown inFIG. 14 be prepared, e.g., by grinding to produce a flat abutment face58 for the abutment collar on the mounting bushing.

Alternatively as shown in FIG. 15 such a plane abutment face 58a can bedesigned in a countersunk way by preparing the end part of the housingby milling. Whether the preparation is made by grinding or milling or inanother way, the acoustic outlet port 54a in the end part of the housing55 is used as a guide for a preparation tool designed for this purpose.

As shown in FIG. 16, at the ready-mounting of a hearing aid in thedesign according to the invention, a hose element 64 can be used with asurplus length which is guided through the acoustic outlet port 64a inthe end part 65 of the housing 61 and fastened hereto by gluing orwelding, whereupon the projecting part of the hose member 64 is cutflush with the abutment face 68 formed by preparation of the end part 65as explained above. By this mounting way, the hearing aid designaccording to the invention can as shown be provided either in the waythat an abutment collar 63 without any mounting bushing is, as shown inFIG. 13, connected directly with the abutment face 68 by gluing orwelding, or by insertion of a mounting bushing 32 with an abutmentcollar 33 with a design as shown, e.g., in FIG. 11 in the end of thehose element 64.

The ready-mounted hearing aid housing 61 with the abutment collar 33 or53 in abutment against the outside of the end part 65 of the hearing aidhousing 61 is shown in FIG. 17.

What is claimed is:
 1. An ear wax guard for placement in an opening in ahousing wall of a hearing aid, said ear wax guard comprising anessentially tubular element, defining a through-going cavity and adaptedfor insertion into the opening with a first end of said tubular elementbeing a leading end as said tubular element is inserted into saidopening from outside said housing, said element having a substantiallysmooth inner wall defining said through-going cavity and having an earwax retaining barrier in form of a screen at said first end.
 2. The earwax guard according to claim 1, wherein said screen forms a radialpattern.
 3. The ear wax guard according to claim 1, wherein said elementat a second end has a collar for sealing abutment against the housingwall.
 4. The ear wax guard according to claim 3, wherein said lip collaris provided with a convex outside and a concave or faintly conicalunderside such that its peripheral edge forms a sealing lip against thehousing wall.
 5. The An ear wax guard according to claim 1 for placementin an opening in a housing wall of a hearing aid, said ear wax guardcomprising an essentially tubular element, defining a through-goingcavity and adapted for insertion into the opening with a first end ofsaid tubular element being a leading end as said tubular element isinserted into said opening from outside said housing, said elementhaving an ear wax retaining barrier in form of a screen at said firstend, wherein said ear wax guard is made of an elastic yielding material.6. The An ear wax guard according to claim 1 for placement in an openingin a housing wall of a hearing aid, said ear wax guard comprising anessentially tubular element, defining a through-going cavity and adaptedfor insertion into the opening with a first end of said tubular elementbeing a leading end as said tubular element is inserted into saidopening from outside said housing, said element having an ear waxretaining barrier in form of a screen at said first end, wherein saidelement is adapted for frictional fitting inside said opening.
 7. Theear wax guard according to claim 6, wherein a said element comprises acircumferential bead providing the frictional fitting.
 8. An ear waxguard for placement in an opening in a housing wall of a hearing aid,said ear wax guard comprising an essentially tubular element adapted forfrictional fitting inside said opening, defining a through-going cavityand adapted for insertion into the opening, said element having firstand second ends with said first end being a leading end as said elementis inserted into said opening from outside said housing, said elementhaving an ear wax retaining barrier in form of a screen at said firstend and a collar for sealing against the housing wall at a second end,said element being made of an elastic yielding material.
 9. The ear waxguard according to claim 8, wherein said screen forms a radial pattern.10. A method for use in the manufacturing of a hearing aid, comprisingproviding a hearing aid housing including a housing wall with a housingwall end part, providing in said end part an acoustic outlet port,providing a bushing with an abutment collar with an oversize in relationto said end part, and finishing said abutment collar by preparation ofits periphery edge to a flush transition with an outside of said endpart.
 11. The method according to claim 10, comprising providing in saidend part a flat abutment face for said abutment collar.
 12. The methodaccording claim 10, comprising providing in said end part a countersunk,flat abutment face.
 13. The method according claim 11, comprisingfitting inside said housing a hose with a surplus length as acousticoutlet canal, guiding said hose through said acoustic outlet port,cutting the projecting length of said hose flush with said abutmentface, and placing said abutment collar directly against said abutmentface and the cut end of said hose to obtain a flush transition with saidabutment face.
 14. The method according claim 13, comprising providingsaid abutment collar in the form of a flat ring disc, and connectingsaid ring disc directly with said abutment face.
 15. The methodaccording claim 13, comprising press-fitting one end of a tubularmounting bushing of said abutment collar in said hose.
 16. An ear waxguard for placement in a hearing aid, said ear wax guard comprising anelement defining a through-going cavity and adapted for insertion intothe hearing aid with a first end of said element being a leading end assaid element is inserted into said hearing aid, said element being madeof a thermoplastic elastomer and having an ear wax retaining barrier atsaid first end.
 17. The ear wax guard according to claim 16, whereinsaid barrier forms a radial pattern.
 18. An ear wax guard according toclaim 16, wherein said element is adapted for frictional fitting insidesaid hearing aid, said element having said first end and a second, saidelement having a collar for sealing against the hearing aid at a secondend, and said element being made of an elastic yielding material.
 19. Anear wax guard according to claim 16, wherein said element is adapted forfrictional fitting inside an opening in a wall of said hearing aid, saidelement having a collar made of a resilient material and having areduced thickness lip at its outer periphery for sealing against thehousing when said element is inserted into said opening.
 20. The ear waxguard according to claim 19, wherein said barrier forms a radialpattern.
 21. An ear wax guard according to claim 16, wherein saidelement is essentially tubular and is adapted for insertion into anopening in a wall of said hearing aid, said element further having a lipat least partially surrounding said tubular element for abutting thehousing wall when said wax guard is inserted, said lip having a reducedthickness outer peripheral edge for resiliently engaging said housingwall.
 22. A method for manufacturing a hearing aid, comprising providinga hearing aid housing including a housing wall with a housing wall endpart with an acoustic outlet port therein, providing an abutment surfacesurrounding said outlet port, and finishing said abutment surface bypreparation of its peripheral edge to a flush transition with an outsideof said housing wall.
 23. A method for manufacturing a hearing aid,comprising providing a hearing aid housing including a housing wall witha housing wall end part with an acoustic outlet port therein, providingan abutment surface surrounding said outlet port, said abutment surfaceat least at its outer periphery being flush with an exterior surface ofsaid housing wall.
 24. A method according to claim 23, furthercomprising the step of providing an inwardly projecting portion thatprojects inwardly from the housing wall at said acoustic outlet port forconnection to a sound tube.
 25. A method according to claim 23, whereinsaid housing is of a form adapted to an individual user's ear canal. 26.A method according to claim 23, wherein said step of providing saidabutment surface includes using said acoustic outlet port as a toolguide.
 27. A method according to claim 22, wherein said abutment surfacecomprises an abutment collar with an over-size in relation to said endpart.